Srinivaspur, Oct 7, 2012, DHNS
The stem borer menace has made its appearance in the mango farms of Srinivaspur taluk.
Mango suffers from several diseases at all stages of its life. All the parts of the plant, namely, trunk, branch, twig, leaf, petiole, flower and fruit are attacked by a number of pathogens including fungi, bacteria and algae.
They cause several kinds of rot, die back, necrosis, blotch, spots and mildew. Some of these diseases, including stem borer menace, are of great economic importance as they cause heavy losses in mango production.
Stem borer is widely distributed in India and attacks a variety of fruit trees including mango. Damage is caused by the grub of this beetle as it feeds inside the stems boring upward resulting in drying of branches and in severe cases attained stem also dies.
Adult beetles, 35-50 mm in size, are stout and greyish brown in colour with dark brown and black spots. Eggs are laid either in the slits of tree trunk or in the cavities in main branches and stems covered with a viscous fluid. Pupation takes place within the stem.
The mango stem borer does not appear in all mango-cultivating areas but in the areas where it is found it causes severe loss.
The important symptoms of the infestation are the holes on the bark due to feeding. The stem borer menace stunts the growth of the mango tree. At later stage of infestation the mango trees dry up.
The pest can be managed by pruning off the infested twigs of tree and destroying the larvae of the insect. They can also be controlled by the use of various chemical applications. Prof Nachegowda of the Horticultural College in Kolar says that the stem borer has been seen mostly in the Badami variety of mango. This is because of the sweetness and taste of the core of the tree trunk, he said.